Caption: Marine plant study. Marine botanist measuring the growth of a Neptune grass plant (Posidonia oceanica) on the sea floor. This plant forms underwater meadows in parts of the Mediterranean Sea, which form a habitat for a variety of other plants and animals. Pollution and drag netting of the seabed have led to a reduction in the plant's numbers. Study of the growth of specimens such as this can allow the population as a whole to be understood with greater accuracy. Photographed in the Mediterranean Sea off France.